Electro-spray ion source for ionisation of esp. high molecular weight thermally labile samples for mass spectrometry - has particle generator disposed w.r.t. extraction chamber entrance orifice such that most particles in generated stream have velocity whose component parallel to linear deflected trajectory is smaller than perpendicular component

摘要

The ionisation source generates ions by electro-spray which are directed such that their directions (23) of travel immediately on formation are resolvable into two perpendicular components, one (26) of which is aligned with a linear first trajectory (14) which passes through an entrance orifice (10), an extraction chamber (15) and into an evacuation port (4) through which the extraction chamber is evacuated. The direction of travel of most particles is such that the component of velocity aligned with the linear first trajectory is smaller than the component (25) perpendicular to it. Ions leave the chamber (15) through an orifice (11) along a second trajectory which is inclined at an angle between 30 and 150 deg. to the linear first trajectory via thew use of a potential gradient in the extraction chamber, prior to passage into a mass analyser. #CMT#USE/ADVANTAGE : #/CMT# For atmospheric pressure chemical ionisation. Has better sensitivity with lower noise and is able to operate for longer periods between maintenance operations.